• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.262-265
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• 1993

Dietary fiber content and carbohydrate digestibility of dried soymilk residue (DSR) and tofu containing DSR were evaluated. Insoluble dietary fiber (IDF) content was 37.4 and 49.8% (%, moisture free basis) for common soymilk residue and DSR, respectively. Both soymilk residues contained 12.5% of soluble dietary fiber (SDF, dry basis). Tofu containing DSR, which is partially substituted with DSR corresponding to 10% weight of soybean used, had higher dietary fiber content (30% more for RDF and 45% more for SDF) than tofu manufactured in traditional manner. Carbohydrate digestibility was much lower in all tofu products ranging from 11% to 21%, and there was a negative correlation( r = -0.9243) between carbohydrate digestibility and total dietary fiber content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.3
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• pp.255-261
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• 1993

The effect of dried soymilk residue (DSR) on protein quality of tofu was studied. The amount of added DSR into soybean water extract was corresponding 10% (dry basis) of soybean used in tofu manufacturing. Proximate composition and in vitro protein qualities of soybeans at different stages of the conversion into tofu have also been investigated. Partially substituted tofu with DSR (TDSR) had higher moisture content (80.6%) than that of tofu prepared in traditional manner (TT). TDSR contained lower content of protein (38.9%) and total lipid (26.9%) compared to 45.8% of protein and 34.3% of total lipid for TT. A large amount of trypsin inhibitor (TI) in raw soybeans was diminished and extracted through tofu processing, and only 10~13% of TI in raw soybean remained in both tofu products (TDSR and TT). There was not a considerable difference in amino acid profiles between TT and TDSR, but TDSR had a higher content of lysine than that in TT. in vitro studies showed that TDSR and TT were comparable in terms of both in vitro digestibilities (90% over for four-enzyme digestibility and predicted digestibility) and discriminant computed protein efficiency ratio (2.07~2.14, DC-PER). Unlike those in vitro indices for protein quality, computed protein efficiency ratio (C-PER) of TDSR was much lower (1.4) than that of TT (1.95). It was revealed that C-PERs of tofu products were not in agreement with rat-PERs (1.7~1.9) in previous reports except for TT. However, DC-PER assay was more recommendable for protein quality of tofu products than C-PER assay.